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8f5875c4e2
This fixes the following security problem: The command-line argument parser in tcpdump before 4.99.0 has a buffer overflow in tcpdump.c:read_infile(). To trigger this vulnerability the attacker needs to create a 4GB file on the local filesystem and to specify the file name as the value of the -F command-line argument of tcpdump. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
102 lines
2.8 KiB
Diff
102 lines
2.8 KiB
Diff
From 8ab211a7ec728bb0ad8c766c8eeb12deb0a13b86 Mon Sep 17 00:00:00 2001
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From: Guy Harris <gharris@sonic.net>
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Date: Wed, 30 Sep 2020 11:37:30 -0700
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Subject: [PATCH] Handle very large -f files by rejecting them.
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_read(), on Windows, has a 32-bit size argument and a 32-bit return
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value, so reject -f files that have more than 2^31-1 characters.
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Add some #defines so that, on Windows, we use _fstati64 to get the size
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of that file, to handle large files.
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Don't assume that our definition for ssize_t is the same size as size_t;
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by the time we want to print the return value of the read, we know it'll
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fit into an int, so just cast it to int and print it with %d.
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(cherry picked from commit faf8fb70af3a013e5d662b8283dec742fd6b1a77)
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---
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netdissect-stdinc.h | 16 +++++++++++++++-
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tcpdump.c | 15 ++++++++++++---
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2 files changed, 27 insertions(+), 4 deletions(-)
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--- a/netdissect-stdinc.h
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+++ b/netdissect-stdinc.h
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@@ -149,10 +149,17 @@
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#ifdef _MSC_VER
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#define stat _stat
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#define open _open
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-#define fstat _fstat
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#define read _read
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#define close _close
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#define O_RDONLY _O_RDONLY
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+
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+/*
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+ * We define our_fstat64 as _fstati64, and define our_statb as
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+ * struct _stati64, so we get 64-bit file sizes.
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+ */
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+#define our_fstat _fstati64
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+#define our_statb struct _stati64
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+
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#endif /* _MSC_VER */
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/*
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@@ -211,6 +218,13 @@ typedef char* caddr_t;
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#include <arpa/inet.h>
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+/*
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+ * We should have large file support enabled, if it's available,
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+ * so just use fstat as our_fstat and struct stat as our_statb.
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+ */
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+#define our_fstat fstat
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+#define our_statb struct stat
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+
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#endif /* _WIN32 */
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#ifndef HAVE___ATTRIBUTE__
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--- a/tcpdump.c
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+++ b/tcpdump.c
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@@ -108,6 +108,7 @@ The Regents of the University of Califor
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#endif /* HAVE_CAP_NG_H */
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#endif /* HAVE_LIBCAP_NG */
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+#include "netdissect-stdinc.h"
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#include "netdissect.h"
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#include "interface.h"
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#include "addrtoname.h"
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@@ -861,15 +862,22 @@ read_infile(char *fname)
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{
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register int i, fd, cc;
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register char *cp;
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- struct stat buf;
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+ our_statb buf;
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fd = open(fname, O_RDONLY|O_BINARY);
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if (fd < 0)
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error("can't open %s: %s", fname, pcap_strerror(errno));
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- if (fstat(fd, &buf) < 0)
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+ if (our_fstat(fd, &buf) < 0)
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error("can't stat %s: %s", fname, pcap_strerror(errno));
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+ /*
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+ * Reject files whose size doesn't fit into an int; a filter
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+ * *that* large will probably be too big.
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+ */
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+ if (buf.st_size > INT_MAX)
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+ error("%s is too large", fname);
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+
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cp = malloc((u_int)buf.st_size + 1);
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if (cp == NULL)
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error("malloc(%d) for %s: %s", (u_int)buf.st_size + 1,
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@@ -878,7 +886,8 @@ read_infile(char *fname)
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if (cc < 0)
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error("read %s: %s", fname, pcap_strerror(errno));
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if (cc != buf.st_size)
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- error("short read %s (%d != %d)", fname, cc, (int)buf.st_size);
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+ error("short read %s (%d != %d)", fname, (int) cc,
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+ (int)buf.st_size);
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close(fd);
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/* replace "# comment" with spaces */
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